A process of encapsulating a variety of ingredients, the process resulting in capsules suitable for incorporation into detergent or personal care compositions.
In many articles of commerce, particularly consumer products, it is desirable to separate certain ingredients, yet have them disposed in a common container. Separation is particularly beneficial where one or more ingredients have negative interactions with each other. For example, in laundry detergents, enzymes are useful in removing stains but it is also best to separate them from other constituents, such as sources of alkalinity and surfactants, especially anionic surfactants like linear alkylbenzene sulfonates or alkyl sulfates. Bleaches, vitamins, perfumes, vegetable oils, plant extracts and ceramides are further examples of ingredients that sometimes need to be separated from the rest of the detergent or personal care composition.
A known technique for separating ingredients in a common container includes encapsulation. Encapsulation technology is well known for different applications. Generally, encapsulation includes a medium that surrounds at least one component and thereby provides a barrier between the xe2x80x9cencapsulatedxe2x80x9d component and other components. The barrier is typically temporary and is designed to break down and release the encapsulated material at a desired time, such as at a particular temperature, upon reaction or dissolution with chemicals, or due to mechanical stress. Methods of encapsulation include coacervation, liposome formation, granulation, coating, emulsification, atomization and spray-cooling.
See, for instance, the disclosures of enzyme encapsulates and encapsulation processes: Falholt et al. (U.S. Pat. No. 4,906,396, UK 2,186 884, and EP 0 273 775), Tsaur et al. (U.S. Pat. Nos. 5,434,069 and 5,441,660), Ratuiste et al. (U.S. Pat. No. 5,589,370). JP 41003667 discloses a dialysis of a protein solution against polyol-base polymer. WO 01/05949 discloses a method for densifying enzyme capsules. See also Mitchnik et al. (U.S. Pat. No. 5,733,531) and Leong (U.S. Pat. No. 5,296,166).
Some of the prior art techniques have particular drawbacks. For example, atomization methods can require special air handling techniques (to avoid respiratory risks). Capsule geometry (size/shape) can also be hard to control. An additional particular problem is to prevent capsule agglomeration after formationxe2x80x94known capsules frequently agglomerate due to tacky hydrophobic encapsulating materials at the capsule surface.
An additional challenge exists when capsules, e.g., enzyme capsules have a lower density than a liquid composition for which they are intended, especially liquid detergent composition. In this case, the density of the enzyme capsule is less than one as a result of the density of the hydrophobe (typical encapsulating material) ranging from 0.8 to 0.9 g/L. Since most liquid detergents have a density of slightly greater than 1, and the density of the enzyme capsule is less than 1, the enzyme capsules will float and form a layer on the top portion of the liquid formulation. Such formulation is unfavorable because a uniform distribution of the capsules is required for the formulation to be delivered consistently, as well as the appearance of the formulation is undesirable. In addition, capsule concentration at the surface of the composition is conducive to further agglomeration.
Consequently, reliable, efficient and cost effective methods of manufacturing encapsulated products are desirable.
The present invention includes a process for forming encapsulated benefit agent and/or colorant for personal care or detergent compositions, the process comprising immersing droplets of an emulsion or a dispersion containing a hydrophobic material and the benefit agent and/or colorant into an aqueous curing solution, the aqueous curing solution containing a high HLB surfactant and/or a super-wetting agent.